Prime-boost immunization using DNA vaccine and recombinant Orf virus protects pigs against Pseudorabies virus (Herpes suid 1)

The present study demonstrates the protective potential of a novel prime-boost vaccination strategy of pigs against lethal Pseudorabies virus (PRV; Herpes suid 1) infection. Animals were primed with Sindbis virus-derived plasmids that express viral glycoproteins gC and gD (gC- and gD-pSIN) and subsequently booster immunized with Orf virus (ORFV; Parapoxvirus) recombinants expressing gC and gD (D1701-VrVgC and -VrVgD). The prime-boost vaccination induced strong humoral and cellular-like PRV-specific immune responses. All prime-boost vaccinated pigs survived the lethal challenge infection without PRV-specific clinical symptoms and presented excellent body weight loss attenuation. Most notably, nasal shedding of challenge virus was reduced by more than about 3 log10, clearly reducing the risk of infection of non-immunized pigs.